1. Field of the Invention
The present invention relates generally to optical switches, and particularly to modular optical switch fabrics.
2. Technical Background
Over the past several decades, fiber optic technology has transformed the telecommunications industry. A decade ago, network designs included relatively low-speed transceiver electronics at each end of a communications link. Light signals were switched by being converted into electrical signals. The electrical signals were switched using electronic switches, and converted back again into light signals. The bandwidth of electronic switching equipment is in the Gigahertz range. On the other hand, the bandwidth of single mode fiber is in the Terahertz range. As the demand for bandwidth increased, network designers have sought ways to exploit the bandwidth in the 1550 nm region. Thus began the development of optically transparent switching fabrics.
In one approach, optical designers have considered using planar optical circuit technology to create space division optical switches. In other approaches, designers have considered using movable MEMS mirrors in planar waveguide arrays to create optical switches. Unfortunately, it is very difficult to create large scale Nxc3x97N optical switch fabrics using these approaches.
In yet another approach being considered, designers are investigating free-space plane-to-plane optical interconnects, referred to as three-dimensional optical cross-connects (3D OXCs). 3D OXCs have the potential to make large scale Nxc3x97N (e.g., 4000 portxc3x974000 port) switching a reality. However, there are several drawbacks to large scale Nxc3x97N switching fabrics. Once demand exceeds the capacity of the Nxc3x97N fabric, the entire fabric must be replaced by a larger fabric. Thus, large replacement costs and service interruptions are incurred. Network managers face the same problem if a portion of the fabric becomes damaged. The entire fabric must be replaced. Finally, designers are having difficulties producing large scale Nxc3x97N fabrics. The alignment between collimator arrays and beam steering arrays must be fixed over the lifetime of the fabric, and under the operating conditions that the fabric is subject to.
What is needed is a modular optical Nxc3x97N switching fabric that allows xe2x80x9cpay-as-you-growxe2x80x9d upgrades. In other words, a switch fabric is needed that can be expanded by simply adding switching capacity as needed. What is also needed is a modular optical Nxc3x97N switching fabric that includes modules that can be replaced and repaired without causing interruptions in service. Smaller fabrics are also advantageous in the sense that a module having a unit array size significantly smaller than the aggregate array size can be more easily produced.
The present invention addresses the needs described above. The present invention provides a modular optical Nxc3x97N switching fabric that allows xe2x80x9cpay-as-you-growxe2x80x9d upgrades. The present invention allows users to expand the switch fabric capacity by simply adding another switch fabric module. The present invention also features a modular optical Nxc3x97N switching fabric having modules that can be replaced and repaired without causing interruptions in service. The optical modules are advantageous because they include smaller fabrics that are more easily produced than large scale fabrics.
One aspect of the present invention is a modular optical switch fabric that includes an optical chassis. At least one optical module is removably coupled to the optical chassis. The at least one optical module includes a collimator panel and a beam steering panel secured to a frame member. The frame member is configured to position the collimator panel in fixed optical alignment relative to the beam steering panel.
In another aspect, the present invention includes a modular optical switch fabric that includes an optical chassis. A reflective element is attached to the optical chassis. At least one optical module is mechanically coupled to the optical chassis and optically coupled to the mirror. The at least one optical module includes a collimator panel and a beam steering panel secured to a frame member. The frame member is configured to position the collimator panel in fixed optical alignment relative to the beam steering panel.
In another aspect, the present invention includes a modular optical switch fabric that includes an optical chassis. At least one pair of optical modules are coupled to the optical chassis. A first optical module of the pair of optical modules is optically coupled to a second optical module of the pair of optical modules. Each optical module includes a collimator panel and a beam steering panel secured to a frame member. The frame member is configured to position the collimator panel in fixed optical alignment relative to the beam steering panel.
In another aspect, the present invention includes a modular optical switch fabric that includes an optical chassis having a chassis connector. At least one optical module has an optical module connector mating with the chassis connector such that the at least one optical module is removably coupled to the optical chassis. The at least one optical module includes a collimator panel and a beam steering panel secured to a frame member. The frame member is configured to position the collimator panel in fixed optical alignment relative to the beam steering panel.
In another aspect, the present invention includes a modular optical switch fabric that includes an optical chassis having at least one first chassis connector and at least one second chassis connector. A reflective element is attached to the optical chassis. At least one pair of optical modules includes a first optical module and a second optical module, the first optical module has a first optical module connector mating with the at least one first chassis connector, and the second optical module has a second optical module connector mating with the at least one second chassis connector, such that the first optical module is optically coupled to the second optical module via the reflective element. Each optical module includes a collimator panel and a beam steering panel secured to a frame member. The frame member is configured to position the collimator panel in fixed optical alignment relative to the beam steering panel.
In another aspect, the present invention includes an optical module for use in an optical switch fabric. The optical module includes a frame member, a collimator panel secured to the frame member, and a beam steering panel secured to a frame member. The collimator panel is in fixed optical alignment relative to the beam steering panel.
In another aspect, the present invention includes a method for directing a light signal in an optical switch fabric. The optical switch fabric includes an optical chassis. The method includes the step of providing at least one optical module removably coupled to the optical chassis. The at least one optical module includes a collimator element and a beam steering element each secured to a frame member. The frame member is configured to position the collimator element in fixed optical alignment relative to the beam steering element. The light signal is input into the optical module via the collimator element, whereby the light signal is automatically directed onto the beam steering element by virtue of the fixed optical alignment provided by the frame.
In another aspect, the present invention includes a method for directing a light signal in an optical switch fabric. The optical switch fabric includes an optical chassis and a reflective element mounted on the optical chassis. The method includes providing at least one pair of optical modules removably coupled to the optical chassis. A first optical module of the pair of optical modules is optically coupled to a second optical module of the pair of optical modules via the reflective element. The first optical module includes a first collimator element and a first beam steering element secured to a first frame member. The first frame member is configured to position the collimator element in fixed optical alignment relative to the first beam steering element. The second optical module includes a second collimator element and a second beam steering element secured to a second frame member. The second frame member is configured to position the collimator element in fixed optical alignment relative to the beam steering element. The light signal is directed into the first optical module via the first collimator element, whereby the light signal is automatically directed onto the first beam steering element by virtue of the fixed optical alignment provided by the first frame. The light signal is steered from the first beam steering element to the second beam steering element via the reflective element, whereby the light signal is automatically directed into the second collimator element by virtue of the fixed optical alignment provided by the second frame.
In another aspect, the present invention includes a method for maintaining an optical switch fabric being used to direct signal traffic. The signal traffic includes light signals being directed from input fibers to output fibers. The method includes providing an optical chassis having a plurality of plug-in slots. The plug-in slots include at least one repair slot. A plurality of first optical modules are inserted into the plug-in slots of the optical chassis. The at least one repair slot is unused. Each optical module includes a collimator element and a beam steering element each secured to a frame member. The frame member is configured to position the collimator element in fixed optical alignment relative to the beam steering element. A maintenance condition is detected. At least one second optical module is inserted into the at least one repair slot in response to the maintenance condition; whereby the signal traffic is not interrupted.
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operation of the invention.